The term “final transmission” or “final drive” is generally used to indicate the transmission part that transmits the torque delivered by the engine to the wheels.
Typically, in industrial vehicles, a final transmission comprises at least one transmission shaft that receives the motion from a differential, possibly associated with a series of reduction gears and/or a brake unit, or from a reducer of various types, or from an electric, hydraulic or other motor.
Examples of such transmissions are described in U.S. Pat. Nos. 4,574,658 and 4,392,396, which provide, in particular, for the use of epicyclic transmission systems to obtain the required final reduction ratio.
However, the known solutions are not effective in cases where the vertical dimensions of the vehicle is restricted or where it is necessary to keep part of the transmission close to the ground.
One example of where this vertical limitation is observed is in the case of vehicles used in the cultivation of orchards, vineyards, olive groves and the like, where vehicles must operate beneath the branches of these plants.
For such applications it is most desired that the motor, and consequently the drive shaft, be located in the lowest possible position, so as to achieve the greatest possible reduction in the vertical dimensions of the vehicle.
However, in order not to frustrate this positioning of the motor and other transmission components, it is also necessary to use small wheels, which are poorly suited to providing traction in the presence of a high power output.
It would, however, be desirable to be able to make full use of the power that the motor is capable of delivering, especially during the different working phases of the vehicle.
Therefore, the technical problem underlying the present invention is that of providing a final transmission that makes it possible to obviate the disadvantages mentioned above with reference to the prior art.